> 1) The ARKit "Face Mesh" seems to be a standard model that is scaled and skewed to fit your face (for example, it ignores glasses, still works if you put your

> 1) The ARKit "Face Mesh" seems to be a standard model that is scaled and skewed to fit your face (for example, it ignores glasses, still works if you put your hand in front of your face, etc). It is _not_ a 3D scan. This is how most (all?) state of the art acquisition methods for standard objects (faces, hands, etc) work. By warping a high res template to fit the data in some optimal manner, you get guarantees on the output topology without having to do tons of messy cleanup.